Electromagnetic brake.



' 'PATENTED MAR. 13, 190g E. KRAMER. Y

ELECTROMAGNETIC BRAKE.

APPLICATION FILED AUG. 3. 190 .1.

rll llllllllllll ll||| 7 brake eonsisting'o the electr'omagn jterrain-STATE PATE T FER EEWIN- KRAMER, or BERLIN, GERMANY.-

' eL'aorfiomneur-zrlc BRA -n To all whom) it may concern.-

ject oil-the King of Prussia, German Emperor, residing at No. 9 Paulstreet, Berlin,

Germany, have invented certain new and useful lmorovernentsiii-Electromagnetic Brakes,

oi which the following isfa spec fication. v, i mvention relates'tobrakes, principall for electrical street-railways, provided wit anelectromagnet, which actuates a'system' or levers and pressesthebralie-blocks' to the. hnwhielsll invention is to produce a an'electromagnet of such a for every, intensity of'curet is -Theobje ct ofm construction hat rent "the armature of theelect'roma moved to edefinite position, and of t e con-- 7 nection of such an electromagnetwith an aparatusdriven by the wheel-axle which regueltes the intensityof the current, .ener 'zmg etin accordance wit the speed of rotat on ofthe wheels. The said magnetic effector attraction ,is attained,

I i owing to the fact that the cross-section of the nth of he lines offorce between the iron ody of the solenoid and thecore is decreased bythe (lee er drawing in of the latter, where by the too, 'gh increase ofthe me: eticforce,

a and the consequent drawing in y starts of he core,is obviated. As,therefore, the'force' with which the brakes are attracted depends uponthe-intensity of the current, so above a certain limit the applicationof the brake 'blocks is proportionate to the velocity of rotation ofthewheels. I attain these objects by the mechanism illustrat drawing, inwhic the operatin' parts are shown in full lines and some deta' s v ofthe carriage indotted llIlGS.

' n 4 I u b I of a coil of wire 1,1nclosed1n an lrolrcasing 2.

The fore extrerrnty The solenoid attractingthe brakesconsists of thecasing is partlall closed by an annular iron shoe 3, which 1s fixedthereon by screws or iamade of such a le core is the like. In the cavityof the coil '1 and' of the shoe 3 an lron core 4 isdisplaceableaidallllpand the core 4 h '0' y that the outer of the sameis ina eeper position then the mneeeiid of theshoe, when the core isdrawn fintdthe coil whereby the cross-section of the Ipathhi the linesoiforce from the shoe to the reduced the moredeeply the core is die" nin, '--By this means the too speedy increase of the magnetic force isobviated, so that the core is not drawn inward deeper than ole-frame,

, sented,'others mightloe ernp tures of which would assumeadefiniteposiin theaccom H Bpeoifiodtion ofLetters'Patent-f iPatntedMarchll3, v Application filed AugustS, 1904., atrium. 219.401."

in .-current for the time being. he core t is provided longitudinalbores and is guided by means of these on bolts 5, the ends of which arefas- 6o tened in the rear wall of the iron casing 2 and ter is ixed'uponthe shoe 3 for mounting the electromagnet on the .vehi- Instead of theelectroxne yed, the armation for each current intensity.

Upon the outer end of the core is fined a 7 rod 7, which,by means ofalink 8 and lever 9 acts upon the usual" brake-rods 1O 11 .12,

which carry the brake-blocks 1'3 and which are taken off by released.

The braking-'electromagnet is preferably energized directly by theelectromotors of the vehicle, which by the intermediaryx-of tliestarting-switch are connected W1 e elec-. troma tion 9 act ascurrent-generators. thatfwithsuchan arrangement the current intensityproduced by the motors of the vependent on the velocityof rotation 85 ofthey wheels. I As, however, as alreadyex plained, the position of thecore corresponds hicle is with the current intensity, the pressure ofthe brake-blocks upon the wheels-is dependent 9 The brake acts 1n thefollowing manner: When the driver desires to apply. the brake,

upon the rotative s eed of these latter. i

'th a number, of

springs 14; when the'lirake is r orresponds to the intensity ofthe'mflgnletlizf I 'in a ca or bridge 6, respective ,whlchlatyes '15serve .I I 5. %net here repre- O et, if necessary," with the interposi-'80' resistance in such a mannerthat they T It is'well-known he.switches the electromotors onto the brake:

electro'ma ets.'- The-motors then generate current, t e strength'ofwhich corresponds '5 .tp the-velocity of rotation of the wheels, so

that the core 4 is drawn into the corresponding (position in the coil anphe with a certain force. the decreased velocity of When, owingtopressure mlmshed tirely without shock. The brakes are like liable toslide, as in this case also the rotative velocity of the Wheels, andconseo'lently the current intensity, decreases. It isthereforeimpossible for" the Wheels to be locked; If, x

the. brake sipthe car and of the 106 wheels the intensity of the currentfells', the

of the brake isalso gradually ditill the vehicle comes to rest enon theother hand, the vehicle should start rolling u onan incline or owing toother causes, -t e current intensity rises and the brakes will beapplied morefirrnly.

Instead of connecting the motor of the vehicle directl with the'brake-electroma gnet, a centrifu a governor might becoupled with thewhee -shaft and switch in current of greater intensity forthe brakeelectromagnet when the s eed of rotation of the wheels was high and owerintensities when the speed. was lower. In this case, however, a sourceof current'which is constant to some extent,

atleast, must be used. i

The brake may be varied in different ways without departing from theprinciple of my invention. I therefore do not wish to be limited to theconstruction illustrated in the drawing; but

What I claim as m invention and desire to secure by Letters atent,is-- 1. In an electromagnetic brake for vehicles, the combination withanelectromagnet,

having a'coil, an ironcasing inclosin the coil,

in conformity with the rotative speed of the wheels; and circuitconnections between the electromagnet and the current-generator,substantially as described. i

2. An electromagnet for vehicle-brakes, 0 having a coil, an iron casinginclosin the coil, an iron shoe closing the open end 0 thejcasing, acentral opening in the shoecoinciding with thehole of the coil, a coreadapted to move axially in the said cavity of the coil and 4 5 shoe, thecore being of such a form that the *eross-section of the path of thelines of force from the shoe to the core its-reduced, when the core isdrawn into the coil, substantiallyas described. 5 3. An electromagnetfor 'vehicle brakes, having a coil, an iron casinginclosing the coil, anannular iron shoe partially'clesing the open end of the casing, acoreadapted to -move axially in the cavity of the coil and 55 shoe, thecorebeing of such a form that the cross-section of the path of the linesof-force from the shoe to the core is reduced, when the core is drawninto the coil, which-electro-' Ina net is energized bythe vehicle-motor,6o wit whichit is short-circuited; in combination with a system ofbrake-levers, substantially as described. A In testimony whereof I havesigned my.

name to this specification inpr'esence of two 65 subscribing witnesses.

ERWIN KRAMER. Witnesses Germs-Bonus, CARL APMAN.

